Support registration confirmations via email

[dcamper]

Some of the following includes changes to downstream applications (Tombolo, RealBI). Rather than create additional issues in those projects and trying to link all of the issues, I will keep them all here for now.

• Auth Service changes
  • Per-application setting enabling email confirmation
    • Requires email provider be defined
    • HPCC hardcoded to not allow email confirmation
  • New database table
    • Used confirmation IDs
      • Contains only those IDs that have been successfully confirmed
  • User account
    • New boolean tracking "confirmed"
      • If service does not enable confirmation, confirmed = true
    • Random ID (UUID?) used in the confirmation
  • Construct and send confirmation email
  • New route to handle confirmation
    • Success
      • Insert random ID into new table of used IDs
      • Delete random ID in user table
      • Text reply to application
    • If random ID not found in user table
      • Check new table of used confirmation random IDs
        • Presence there changes textual reply
• Application (Tombolo, RealBI) changes
  • New route to handle email confirmation
    • Success will be a simple "thank you" — do not login
  • Customized text reply to user during registration, based on Auth Service response
    • "Check your inbox…."
    • "Thank you for registering…"
• Other stuff
  • Email confirmations that die - auth service sent it, but no reply
    • Scheduled process finds orphaned confirmations and deletes the user
      • 24 hour?
  • Unconfirmed user and user tries to register again
    • Treat that user as if we have not seen them before
    • Overwrite old user info, generate new random ID, send new confirmation email, etc
      • Send email message slightly, indicating that it is a resend
  • Registering with different application, same user info
    • Auth Service replies to application with message telling them about existing account
    • Do not send confirmation email (if they are already confirmed)